Laser diodes are being used nowadays in very large numbers and in a very wide variety of applications in various industrial fields. For example, laser diodes are to be found in medical applications (diagnosis, photodynamic therapy, etc.), in the field of telecommunications (emitting optical signals conveyed by optical fiber), in the field of telemetry, etc.
Depending on the application, the power supply current for a laser diode, i.e. the current flowing through the diode between an anode and a cathode thereof, may lie in the range a few milliamps to several hundreds of amps. The laser diode is driven by a driver member that is dimensioned mainly as a function of the power supply current required in the application. In conventional and non-exclusive manner, such a driver member comprises power supply means supplying electrical energy used to power the components of the driver member and to generate the power supply current for the laser diode, a current regulator module adapted to regulate the power supply current for the laser diode, limiter means for limiting the power supply current for the laser diode in order to protect it, and sometimes a photodiode producing current that is substantially proportional to the light intensity generated by the laser diode, and that is used for verifying that the driver member is operating properly, and possibly also for regulating the power supply current for the laser diode, etc.
The energy efficiency of an assembly constituted by a driver member and a laser diode is a parameter of major importance in numerous applications, and in particular in portable applications in which the driver member is powered by a battery of limited capacity. In general, in order to improve the efficiency of such an assembly, attempts are made to improve the internal structure of diodes (e.g. attempts are made to reduce losses of light due to photons being absorbed by free charge carriers so as to reduce the power supply current needed by diodes), or indeed to design current regulator modules that are more efficient.
It is thus possible to improve the efficiency of such an assembly, but such improvement is generally accompanied by expensive development efforts and/or by changes to electrical circuit diagrams that tend to make the driver member more complex.